A short time later there were reports of three men carrying knives at Borough Market and a witness reported seeing armed police shooting at Brindisa tapas bar.

Scotland Yard confirmed that 12 people were arrested at a raid on addresses across Barking this morning.

Prime Minister Theresa May said:

Following updates from police and security officials, I can confirm that the terrible incident in London is being treated as a potential act of terrorism.

This is a fast moving investigation. I want to express my huge gratitude to the police and emergency services who are on the scene. Our thoughts are with those who are caught up in these dreadful events.

Footage was released of people in the Borough Market basement hiding for cover.

BBC reporter Holly Jones was on the bridge at the time of the incident and gave BBC News an eye-witness report, saying the van was driven by a man and was “probably travelling at about 50 miles an hour”.